The field of cap and tube assemblies which carry medicines, vitamins and the like, have become of major importance and interest in the pharmaceutical industry. There are many such devices, and recently interest has focused on those applications in which two ingredients are kept separate from one another in a single container, such as in a dual chamber dispensing package. At the appropriate time, the multiple components can be used for the intended purpose. Prepackaging of specific doses or quantities is important to save time during the application of medicine or chemicals which need to be mixed promptly or in precise quantities.
Often times, potent drugs which rapidly deteriorate when mixed together are easily and safely maintained in dual chambers to avoid premixing. Since these drugs are often used by geriatric patients who may be limited in their ability to mix in accurate proportions, it is particularly advantageous for them to have the drugs kept apart and mixed accurately just before use.
Multiple container closures are not new per se. In my prior patent, U.S. Pat. No. 4,884,703, a double compartment closure and tube assembly is disclosed which has certain features which have been found to be quite acceptable in a number of markets. Specifically, my patent discloses a container with two adjacent compartments having a common surface at one end with a thin wall portion at that end for each surface. The cap slideably fits on the end of the container and includes puncture means or piercers which are in alignment with the walls so that the movement of the cap will cause the piercers to puncture the thin wall portion of each compartment. The cap is placed in a first position on the end of the container by cooperation between an interference surface ad a surface of resistance. Typically, those surfaces are formed by a ring and groove arrangement.
Another dual compartment container is described in my co-pending application titled DUAL CHAMBER DISPENSING PACKAGE, filed Oct. 30, 1991, and having Ser. No. 07/784,964. In this application, a multiple compartment chamber is disclosed which is normally sealed at one end, such as by a crimp seal, and has a discharge opening at the other end. At least two adjacent compartments are provided for chemical reactants, medicines and the like. Each compartment is aligned at the discharge end and has a thin wall dispensing port for discharge of the contents once the thin wall has been broken.
The device in my co-pending application contemplates the use of bellows means which are formed from the compartments for applying a discharge force to the individual compartments upon squeezing the container. In a preferred embodiment, there are two compartments sharing a common wall which are axially aligned and pivotally joined. These two compartments form a hinge point. Thus, particularly when high viscosity fluids are employed, squeezing the walls of the containers causes the bellows to force fluid out of the discharge ports at a much faster fate than would be achieved by gravity alone.
In most cases when the compartments are made from plastic or other quite flexible materials, designs of the type described above are admirably suited for their intended purposes. Medicines and the like are effectively dispensed and the precise quantity of contents needed is placed at the point where it is most needed. This design is particularly effective in providing precise proportions of two or more ingredients at the point where it is dispensed while at the same time providing a positive force for dispensing the contents. The bellows principle has been found to be particularly helpful, especially with different quantities or viscosities of the two or more fluids in the various containers.
The only drawback to the general field of multiple compartment containers is that sometimes the materials from which the containers are manufactured is too stiff or too inflexible. When small container chambers are needed, for example when eye drops, vitamins, or other small dosage medicines and treating fluids are dispensed, the material from which the containers are formed may prevent ease of sealing. Specifically, when designs such as described in my co-pending application and in my aforementioned U.S. Pat. No. 4,884,703 and others are employed, it is sometimes difficult to seal the end which is used for filling the containers. When bellows like structures are used, particularly on small or stiff compartments, the stress on the end which is to be sealed is potentially too great to permit a complete and effective seal to be achieved.
Another dual compartment container is described in my co-pending application titled DUAL CHAMBER DISPENSING PACKAGE, filed Jan. 31, 1992, and having Ser. No. 07/828,516. In this application, a dual compartment container assembly has been provided which includes two adjacent compartments which are separated by a common wall segment. The container includes a discharge end which is operable to permit dispensing of the contents of said container, and a filling end which is sealed after contents are placed in said compartments. The two adjacent compartments have outer arcuate walls which extent from the common wall segment to form the compartments. The common wall segment has a first width prior to filling and a second longer width after the filling end is sealed to form a seal at the filling end. In a preferred embodiment, the common wall segment is pleated to have a first length prior to filling and a second straightened longer width after the filling end is sealed.
This invention contemplates the use of bellows on the opposed outer ends of both chambers so that effective pressure can be applied to the insides of the chambers to force the full dosage out of the chamber. While this is effective, particularly in designs where the tube material is flexible and where the size of the container is sufficiently large, there is one drawback to this design when the container is small and relatively rigid.
Under some circumstances, the inclusion of the two outer walls, the center or common wall, and the folded overlap from the two bellows like portions of the outer walls results in a configuration where 5 or more thicknesses are being compressed at the filling end. It is sometimes difficult to achieve a complete seal that has integrity and reliability that satisfies even the most strict standards. Additionally, the pleated center wall is formed with its own stresses due to the "memory" of the plastic. These stresses form some kind of resistance to a perfectly reliable seal at this filling end. This can place an undue stress on the heat seal or other closure and cause a problem in expelling all of the contents of the two compartments of the container. More important is the concern that the seal may not keep its integrity for the useful life of the container. There is the possibility that this undue stress may cause the common wall to crack or separate, causing the contents to mix at the wrong end of the container.
Accordingly, it is an object of this invention to provide a simple and effective design for dual compartment containers which permits a safe and complete seal of the filling end of the container.
Another object of this invention is to provide a sealing system for dual compartment containers which are small and relatively inflexible compared to larger containers, and yet which permits all of the contents to be expelled.
Yet another object of this invention is to provide a seal design for use with dual compartment containers which employ pressure dispensing features such as bellows shaped containers and the like in a manner which allows for complete expulsion of the contents while maintaining seal integrity.
Other objects will appear hereinafter.